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Publication numberUS4687397 A
Publication typeGrant
Application numberUS 06/738,960
Publication dateAug 18, 1987
Filing dateMay 29, 1985
Priority dateMay 29, 1985
Fee statusLapsed
Publication number06738960, 738960, US 4687397 A, US 4687397A, US-A-4687397, US4687397 A, US4687397A
InventorsImre Berecz
Original AssigneeMicrodot Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Composite rivet with strippable mandrel
US 4687397 A
Abstract
A composite rivet comprises an integral mandrel having a collar telescoped thereabout for controlling radial deformation of a head forming portion thereof.
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Claims(4)
I claim:
1. A composite rivet comprising
a preformed head portion,
a shear portion,
a head forming portion integral with said shear portion,
an integral mandrel extending from said head forming portion, and
a collar having an inside diameter greater than the initial outside diameter of the head forming portion of said rivet, said collar being telescoped about and radially aligned with said head forming portion for controlling radial deformation thereof,
said head forming portion being strippable from said mandrel and deformable radially outwardly to the inside diameter of said collar to lock said collar against axial movement away from the preformed head portion of said rivet.
2. A composite rivet in accordance with claim 1 wherein said collar has a truncated upwardly divergent conical cavity therein for the acceptance of the head forming portion of said rivet.
3. A composite rivet comprising
a preformed head portion,
a shear portion,
a head forming portion integral with said shear portion,
an integral mandrel extending from said head forming portion, and
a collar having a truncated upwardly divergent conical cavity therein telescoped about and radially aligned with said head forming portion for controlling radial deformation thereof,
said collar being reinforced with circumferentially extending fibers,
said head forming portion being stripped from said mandrel and extending radially outwardly to lock said collar against axial movement away from the preformed head portion of said rivet.
4. A method of installing a composite rivet comprising a preformed head portion, a shear portion, a head forming portion, and an integral mandrel extending centrally of said head, shear and head forming portions and away from the head portion thereof, said method comprising the steps of
installing said rivet in an aperture in a workpiece,
assembling a collar about the head forming portion of said rivet for controlling deformation thereof,
heating said preform, and
stripping said head forming portion away from said mandrel portion to form an integral head on said rivet while maintaining the mandrel portion of said rivet.
Description
BACKGROUND OF THE INVENTION

The rivet of the instant invention is an improvement on the composite rivet disclosed in U.S. Pat. No. 4,478,544 issued Oct. 23, 1984, for Composite Rivet, and assigned to the assignee hereof.

Carbon fiber reinforced materials are widely used in the aircraft industry for airframe structural components. However, one characteristic of composite materials utilizing carbon fibers is that the carbon fibers are difficult to reform. Thus, the use of carbon fiber reinforced resins in rivets has heretofore been limited by the difficulty of efficiently forming the rivet heads.

SUMMARY OF THE INVENTION

The aforesaid problem is solved by the discovery that a rivet head can be formed by stripping the radially outermost carbon fibers and their encapsulating thermoset resin matrix from an integral internal mandrel that is tensioned relative to a workpiece. Stripping and compression of the fibers and resin matrix by a suitable tool is enabled by the use of a thermoplastic or "B"-stage thermoset resin matrix, which is softened due to the application of heat. To install the rivet, a filament wound or braided fiber reinforced plastic collar is telescoped over a head forming portion of the rivet. A portion of the fiber and resin matrix is thereafter stripped from an integral mandrel and compressed into the collar to form a radially extending rivet head that is integral with the shear portion of the rivet. A riveted connection is formed that exhibits relatively high shear and tensile strength.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional elevational view, of a preferred embodiment of the rivet of the instant invention; and

FIG. 2 is a view of the rivet of FIG. 1 after advancement of a forming tool concurrently with tensioning of the rivet mandrel to form a head on the installed rivet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

As best seen in FIG. 1 of the drawings, a rivet 10 in accordance with a constructed embodiment of the instant invention comprises a thermoplastic or "B"-stage thermoset resin preform 11 having a preformed head portion 12, a shear portion 14, and a head forming portion 16. The preform 11 is reinforced by parallel carbon fibers 17 and a woven Kevlar sheath 18.

An integral mandrel 19 extends from the upper end of the head forming portion 16 of the preform 11 to facilitate tensioning of the rivet 10.

A fully polymerized thermoset plastic collar 20 having filament wound or braided carbon or Kevlar fibers 21 therein is disposed about the head forming portion 16 of the preform 11 to control deformation thereof. It is to be noted that the collar 20 has a truncated conical internal cavity 22 that diverges in the direction of the mandrel portion 19 of the preform 11 whereby the collar 20 is locked against the workpiece 24.

As seen by comparing FIG. 1 with FIG. 2 of the drawings, the mandrel 19 of the preform 11 is adapted to be pulled upwardly by a tensioning tool (not shown) of conventional design while a head forming tool 30 is concomitantly biased downwardly against a shoulder 32 on the head forming portion 16 of the preform 11 resulting in deformation of head forming portion 16 of the preform 11 into a conical head 34 illustrated in FIG. 2. The conical configuration of the head 34 locks the collar 20 against the workpiece 24 and aids in establishing the significant pullout strength exhibited by the rivet 10. It is to be noted that the reformed head 34 has an annular shoulder 36 in engagement with the workpiece 24.

In accordance with the instant invention, the head forming portion 16 of the preform 11 is stripped or separated from the mandrel portion 19 thereof. Such stripping is practical because the carbon fibers 17 are orientated parallel to one another and to the direction of movement of the tool 30. Moreover, the fibers 17 are separated from one another by the resin matrix which is softened by the application of heat by, for example, a hot air blast, preheat of the head forming tool 30, preheat of the entire preform 11, or heating of the entire rivet assembly 10 in situ.

While the preferred embodiment of the invention has been disclosed, it should be appreciated that the invention is susceptible of modification without departing from the scope of the following claims.

Patent Citations
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US4478544 *Jun 4, 1982Oct 23, 1984Microdot Inc.Composite rivet
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4861211 *Oct 17, 1988Aug 29, 1989Lockheed CorporationComposite rivet
US4863330 *Jul 15, 1987Sep 5, 1989Northrop CorporationComposite fastener and method of manufacture
US4975006 *May 25, 1990Dec 4, 1990General Dynamics Corporation, Convair DivisionCarbon-carbon fasteners, bolt type
US5022803 *May 25, 1990Jun 11, 1991General Dynamics Corporation, Convair DivisionPin type carbon-carbon fastener
US5033925 *Dec 16, 1988Jul 23, 1991The B. F. Goodrich CompanyComposite nut and bolt
US5057257 *Feb 20, 1990Oct 15, 1991Quantum Composites, Inc.Method of transfer molding fiber-reinforced resin bolt products
US5080547 *Mar 30, 1990Jan 14, 1992The B. F. Goodrich CompanyTriaxially braided composite nut and bolt
US5086997 *Apr 2, 1990Feb 11, 1992The Boeing CompanyStructural joint and a method for joining in reinforced thermoplastic fabrication
US5090857 *Jan 31, 1991Feb 25, 1992The United States Of America As Represented By The Administrator Of The National Aeronautics And Space AdministrationMetallic threaded composite fastener
US5092727 *Dec 16, 1988Mar 3, 1992The B. F. Goodrich CompanyBraided composite threaded member
US5114290 *Dec 16, 1988May 19, 1992The B. F. Goodrich CompanyFiber reinforced composite threaded member
US5127783 *May 25, 1989Jul 7, 1992The B.F. Goodrich CompanyCarbon/carbon composite fasteners
US5209888 *Aug 9, 1989May 11, 1993Fukuvi Chemical Industry Co., Ltd.Method for producing frp screw-like fastening elements
US5354160 *Aug 7, 1992Oct 11, 1994Textron Inc.Composite fastener
US5938386 *May 4, 1998Aug 17, 1999Senco Products, Inc.Fastening device
US6398450 *Aug 19, 1999Jun 4, 2002British Aerospace Public Limited CompanyFastener arrangements
US6646240May 14, 2002Nov 11, 2003British Aerospace Public Limited CompanyFastening arrangements
US6757483Apr 28, 2000Jun 29, 2004Pioneer Electronic CorporationInformation recording medium with aggregate attribute information recorded in video manager, apparatus for recording the same and apparatus for reproducing the same
US7150594 *Mar 9, 2004Dec 19, 2006The Boeing CompanyHybrid fastener apparatus and method for fastening
US7351022Sep 30, 2004Apr 1, 2008Denslow Clark AUnified multi-part head for a staked fastener
US7384226 *Apr 15, 2004Jun 10, 2008Newfrey LlcBlind fastener
US8226871 *Dec 26, 2007Jul 24, 2012Honda Motor Co., Ltd.Heat staking process with increased retention force
US8393068 *Nov 6, 2007Mar 12, 2013The Boeing CompanyMethod and apparatus for assembling composite structures
US8474759Aug 10, 2009Jul 2, 2013The Boeing CompanyMethod and apparatus for fastening components using a composite two-piece fastening system
US20040218908 *Jun 2, 2004Nov 4, 2004Pioneer Electronic CorporationInformation recording medium, apparatus for recording the same and apparatus for reproducing the same
US20040228706 *Apr 15, 2004Nov 18, 2004Jones Steven V.Blind fastener
US20050201845 *Mar 9, 2004Sep 15, 2005The Boeing CompanyHybrid fastener apparatus and method for fastening
US20060062650 *Sep 20, 2004Mar 23, 2006The Boeing CompanyHybrid fastener apparatus and method for fastening
US20060067806 *Sep 30, 2004Mar 30, 2006Denslow Clark AUnified multi-part head for a staked fastener
US20080230948 *Dec 26, 2007Sep 25, 2008Christopher SalvadorHeat staking process with increased retention force
US20090119860 *Jan 13, 2007May 14, 2009Klaus AmselRiveted joint based on plastic
US20090126180 *Nov 6, 2007May 21, 2009Keener Steven GMethod and apparatus for assembling composite structures
US20100001137 *Jan 7, 2010The Boeing CompanyMethod and Apparatus for Fastening Components Using a Composite Two-Piece Fastening System
US20130340239 *Mar 1, 2012Dec 26, 2013Nihon UniversitySubstrate joining method using rivet, and joining structure
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Classifications
U.S. Classification411/503, 411/361, 411/377, 411/508, 411/901
International ClassificationF16B19/04, B29C65/60, F16B19/06
Cooperative ClassificationB29C66/41, B29C66/7392, B29C66/7212, B29C66/7394, Y10S411/901, B29C65/601, F16B19/06, B29C66/8322, B29C66/80, B29K2105/101, F16B19/04, B29C66/81423
European ClassificationB29C66/80, B29C65/60B, B29C66/8322, F16B19/04, F16B19/06
Legal Events
DateCodeEventDescription
May 29, 1985ASAssignment
Owner name: MICRODOT INC., 23 OLD KINGS HIGHWAY SOUTH, DARIEN,
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BERECZ, IMRE;REEL/FRAME:004435/0738
Effective date: 19850523
Dec 3, 1990FPAYFee payment
Year of fee payment: 4
Jan 11, 1994ASAssignment
Owner name: KAYNAR TECHNOLOGIES INC., A DE CORP., CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MICRODOT INC., A DE CORP.;REEL/FRAME:006830/0380
Effective date: 19940103
Jan 12, 1994ASAssignment
Owner name: GENERAL ELECTRIC CAPITAL CORPORATION, CONNECTICUT
Free format text: SECURITY INTEREST;ASSIGNOR:KAYNAR TECHNOLOGIES INC. A DELAWARE CORPORATION;REEL/FRAME:006826/0558
Effective date: 19940103
Mar 28, 1995REMIMaintenance fee reminder mailed
Aug 20, 1995LAPSLapse for failure to pay maintenance fees
Oct 31, 1995FPExpired due to failure to pay maintenance fee
Effective date: 19950823
Jun 10, 1999ASAssignment
Owner name: KAYNAR TECHNOLOGIES, CALIFORNIA
Free format text: RELEASE OF SECURITY INTEREST;ASSIGNOR:GENERAL ELECTRIC CAPITAL CORPORATION;REEL/FRAME:010007/0689
Effective date: 19990420